Why does the Torah add a 'Vav' in the word "ve'Korbano"?
Hadar Zekeinim (12), Ba'al ha'Turim: This hints at Nachshon's six descendents, each of whom will be blessed with six Berachos (Moshav Zekeinim (12) - six Midos) - David, Mashi'ach, Daniel, Chananyah, Misha'el and Azaryah. 1
Rashbam, Ibn Ezra, Moshav Zekeinim: Following "Vay'hi ha'Makriv ba'Yom ha'Rishon... ", it is correct to continue "v'Korbano ... ", with a 'Vav'.
Da'as Zekeinim, Moshav Zekeinim: To prevent Nachshon from becoming conceited for being the first to bring his Korban. "V'Korbano" connotes that he was not first.
See Ba'al ha'Turim, who elaborates and gives additional answers to the question.
Shabbos 87a: The day had 10 crowns (firsts. - Those not listed here are [the first] day of creation (Sunday), day of Chanukas ha'Mizbe'ach, fire descending from Heaven, Achilas Kohanim of Korbanos, Isur Bamos, and the Shechinah descending to Machaneh Yisrael.) Due to this, Da'as Zekeinim (17) rejects a similar Drashah about six Chidushim of the day.
I.e. it began the first full year from Yetzi'as Egypt. (PF)
I did not find anyone else say so. Seder Olam and all other Meforshim say that the Parah was burned on the second. Gitin 60a says that Parshas Parah Adumah was said on the first.
What kind of flour-offering did the Nesi'im bring?
Rashi: They brought a Minchas Nedavah. 1
And not a Minchas Nesachim - that accompanies another Korban (See Sifsei Chachamim).
What is the significance of the variety of Korbanos that they brought?
Why did the Nesi'im bring "Ka'aras Kesef Achas" (one silver dish) and "Mizrak Echad Kesef" (one silver basin)?
Rashi 1 (on Pasuk 19, citing R. Moshe ha'Darshen): The Gematriya of Ka'aras Kesef (930) corresponds to the years that Adam ha'Rishon lived, whereas the Gematriya of Mizrak Echad Kesef (520) corresponds to No'ach's age when he first had children (500), and 20 years prior to that, when the decree to destroy the world was issued.
Ramban (2, from Bamidbar Rabah 13:14): They correspond to the two kings who were destined to descend from Nachshon - Shlomo and Mashi'ach and who will rule over the sea and dry land. The dish symbolizes the sea, which surrounds the land and is like a dish. The bucket alludes to this world, which is like a ball. 2
Rashi explains the intent of the Korbanos of Nesanel ben Tzu'ar (verses 19-23), for he says that Nesanel suggested to the Nesi'im to bring these Korbanos. I.e. they all intended like he did. (EC) Others disagree; refer to 7:18:1:2,3,4.
Which is thrown - "Mizrak" - from hand to hand. See R. Chavel's footnotes.
Seeing as, based on the word "Sheneihem" (See Peninim mi'Shulchan ha'Gera) implies that the amounts of flour in the dish and in the basin were equal, how come that the dish weighed a hundred and thirty Shekel and the basin, only seventy?
Targum Yonasan: Because the wall of the dish was thicker than that of the basin.
What is the significance of the weight 130?
Rashi (19, citing R. Moshe ha'Darshen): Corresponding to the age of Adam ha'Rishon, when he gave birth 1 (to Sheis - Ba'al ha'Turim).
Ramban (2, from Bamidbar Rabah 13:14): It corresponds to the 'Yamim' (Gematriya - 100) that Hashem created on the third day, and the Yam that Shlomo added, whose circumference was 30 Amos. 2
Da'as Zekeinim, Hadar Zekeinim (19), Rosh (12): This is the age of Yocheved when she gave birth to Moshe.
What is the significance of "Shiv'im Shekel"?
Rashi (19, citing R. Moshe ha'Darshen): Corresponding to the 70 nations that descended from Adam.
Ba'al ha'Turim #1: Corresponding to the 70 souls who went down to Egypt. 1
Ba'al ha'Turim #2: Corresponding to the 70 years that Adam left for his children 2 and to save Yisrael from the 70 nations.
Ramban (2, from Bamidbar Rabah 13:14): Corresponding to the 70 nations over whom Shlomo and Mashi'ach will rule.
Da'as Zekeinim, Hadar Zekeinim (19), Rosh (12): This corresponds to Moshe, who was equal to 70 Zekeinim of the Sanhedrin.
What is the significance of "Sheneihem Mele'im So'les"?
Ramban (2, from Bamidbar Rabah 13:14): All nations will bring gifts to Shlomo and Mashi'ach; they are praised like fine gold ("ha'Mesula'im ba'Paz" - Eichah, 4:2).
Da'as Zekeinim: Moshe and Aharon are equal.
What is the significance of "Belulah ba'Shemen "?
Ramban (2, from Bamidbar Rabah 13:14): Corresponding to Shlomo and Mashi'ach's good name - "Tov Shem mi'Shemen Tov (Koheles, 7:1).
What is the significance of "Kesef"?